How to achieve return to top in php

Return to top is a function that allows users to easily return to the top of the web page. If the web page content is long, users will need to keep sliding up when scrolling the page, which will make users feel tired and inconvenient. Therefore, adding a return to top function is very necessary.

Here, we will introduce the use of PHP to implement the function of returning to the top.

Basic knowledge

To implement the return to top function, we need to master the following two knowledge points:

JavaScript

Realize the return to top function on the web page , the most important thing is to use JavaScript scripting language. JavaScript is a client-side scripting language. By embedding JavaScript scripts in HTML, dynamic effects can be displayed and interacted with.

PHP file contains

When we need to reuse certain code logic, referencing external files is a good way. PHP provides the file include function, which allows us to separate code from HTML and make code logic reusable and maintainable.

Implementation process

Based on the above basic knowledge, we can implement this return to top function. The following is the specific process to implement this function:

1. Write a JavaScript script

First, we need to write a JavaScript script and save it in a separate .js file, for example, In a file named "scroll.js":

window.onscroll = function() {
    scrollFunction()
};

function scrollFunction() {
    if (document.body.scrollTop > 20 || document.documentElement.scrollTop > 20) {
        document.getElementById("scrollBtn").style.display = "block";
    } else {
        document.getElementById("scrollBtn").style.display = "none";
    }
}

function scrollTopFunction() {
    document.body.scrollTop = 0;
    document.documentElement.scrollTop = 0;
}

This code will register a scroll bar listening event and two functions, which are used to determine whether to display and hide the return button, and to implement the return action. .

2. Create a return button

Create a button element in the HTML file. When the user clicks, the scrollTopFunction() function defined in JavaScript will be called to perform the return Operation:

<button onclick="scrollTopFunction()" id="scrollBtn" title="返回顶部">&#9650;</button>

The id attribute of the button element is scrollBtn, and the onclick attribute is used to register a click event, which will call scrollTopFunction() Function to implement the operation of returning to the top.

To facilitate maintenance and reuse of code, we write this HTML code in a separate file scroll-btn.html, and then include it as a variable to index. php In the file:

<?php
    $scrollBtn = file_get_contents("scroll-btn.html");
?>

3. Introduce JavaScript script and return button

Add the following code to the JavaScript and HTML files we introduced before in the page:

<?php echo $scrollBtn;?>
<script src="scroll.js"></script>

This will contain the back button and JavaScript defined in the previous step.

4. Complete code

The following is the complete PHP code:

    
    
    


    
    
PHP Scroll to Top Button
    

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<?php echo $scrollBtn;?>
<script src="scroll.js"></script>

Summary

So far, we have learned to use PHP and JavaScript to Add the ability to return to the top. This feature helps users browse page content more easily and improves user experience and overall page quality. I hope this article can help readers who need to implement this function.

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